Statement of the Technical Field
The inventive arrangements relate to unmanned ground vehicles, and more particularly to improvements in suspensions systems used in unmanned ground vehicles.
Description of the Related Art
An unmanned ground vehicle (“UGV”) requires a suspension system that supports a wide range of capabilities. For example, a UGV suspension system must provide good off-road mobility and must perform well on rocks, dirt, snow, and inclines. Further, a UGV suspension system must exhibit good mobility on man-made structures such as stairs and curbs. A UGV typically also includes a manipulator arm. Accordingly, as a further requirement, a UGV suspension system should provide good stability during manipulation operations where the manipulator arm has large horizontal reach and is used to lift heavy objects.
In an effort to satisfy all of these requirements, various UGV suspension systems have been proposed. The simplest approach can involve fixed tracks and/or wheels (i.e. no suspension). However, such an arrangement offers little in the way of mobility benefit. Another approach involves a plurality of elongated flippers which pivot on one end. Each flipper has a moving track which extends around the flipper. Although effective, multiple tracked flippers are complex, expensive and offer poor manipulation support. Another UGV suspension option is an independent wheel suspension in which each wheel moves independently on a resilient member. However, these systems provide poor manipulation support because they allow the UGV chassis to shift when a manipulator arm places heavy torque loads on the UGV chassis. Rocker-bogie suspension systems are also known in the art. Such systems have excellent passive conformal capabilities for a wide variety of terrain. However, they offer poor manipulation support, especially under conditions where a manipulator arm exerts heavy torque loads on the UGV chassis.